Republican leaders tiptoe around the smear campaign against Obama's faith and citizenship.

Will Saletan writes about politics, science, technology, and other stuff for Slate. He’s the author of Bearing Right.

Six months ago on Meet the Press, NBC's David Gregory asked Senate Republican Leader Mitch McConnell about a survey in which 31 percent of Republicans said President Obama was a Muslim. McConnell demurred: "I think the faith that most Americans are questioning is the president's faith in the government to generate jobs." Gregory persisted: "As a leader of the country, Sir—as one of the most powerful Republicans in the country—do you think you have an obligation to say to [31] percent of Republicans in the country … who believe the president of the United States is a Muslim, 'That's misinformation'?"

The best McConnell would do was this: "The president says he's a Christian. I take him at his word."

Well, that was half a year ago. And McConnell was just one Republican leader. And if he didn't explicitly denounce the Obama-Muslim conspiracy theories, as Gregory had requested, perhaps that was a result of being surprised by the question.

But since then, the leadership's pattern of cowardice in the face of Obamaphobic falsehoods has grown.

On Jan. 6, John Boehner's first day of business as speaker of the House, a heckler in the chamber challenged Obama's citizenship. NBC's Brian Williams asked Boehner: "You've got 12 members co-sponsoring legislation that does about the same thing: It expresses doubt [about Obama's citizenship]. Would you be willing to say: 'This is a distraction. I've looked at it to my satisfaction. Let's move on'?" Boehner replied: "The state of Hawaii has said that President Obama was born there. That's good enough for me." For me, lest anyone feel that the speaker was imposing his personal beliefs.

Williams persisted: "Would you be willing to say that message to the 12 members in your caucus who seem to either believe otherwise, or are willing to express doubt and have co-sponsored legislation?"

Boehner answered: "Brian, when you come to the Congress of the United States, there are 435 of us. We're nothing more than a slice of America. People come regardless of party labels. They come with all kinds of beliefs and ideas. It's the melting pot of America. It's not up to me to tell them what to think."

Not up to me. Obama's citizenship, like one's religion or favorite color, is a matter of personal belief. Think what you want to.

On Jan. 23, Gregory asked House Majority Leader Eric Cantor: "There are elements of this country who question the president's citizenship, who think that his birth certificate is inauthentic. Will you call that what it is, which is crazy talk?" Cantor replied, "I don't think it's nice to call anyone crazy." Gregory asked: "Is it a legitimate or an illegitimate issue?" Cantor answered: "I don't think it's an issue that we need to address at all." So Gregory made the case for addressing it: "I feel like there's a lot of Republican leaders who don't want to go as far as to criticize those folks."

Cantor, like Boehner and McConnell, spoke for himself but refused to repudiate the conspiracy theorists. "I think the president's a citizen of the United States," he said. "Why is it that you want me to go and engage in name-calling?"

David, it's not my job to tell the American people what to think. Our job in Washington is to listen to the American people. Having said that, the state of Hawaii has said that he was born there. That's good enough for me. The president says he's a Christian. I accept him at his word.

Again, Boehner was answering in terms of his own beliefs. And when Gregory asked him whether the Muslim theory was "nonsense," Boehner softened his affirmation of Obama's version. "I just outlined the facts as I understand them," said Boehner. As to anyone else's beliefs to the contrary, he shrugged, "Listen, the American people have the right to think what they want to think. I can't—it's not my job to tell them."

How about the members of Boehner's own caucus? Is it his job to tell them when they're spreading falsehoods? Gregory asked the speaker:

You had a new Tea Party freshman who was out just yesterday speaking to conservatives, and he said, "I'm fortunate enough to be an American citizen by birth, and I do have a birth certificate to prove it." That was Raul Labrador … a congressman from Idaho. Is that an appropriate way for your members to speak?

Boehner dismissed the comment as probably a joke. But he repeated, "It really is not our job to tell the American people what to believe."

That's four straight interviews in which the country's three top Republicans—the speaker of the House and the GOP leaders in each chamber—have refused to condemn the spreading of lies about Obama's faith and citizenship. These three men are confident enough in the personhood of fetuses to support banning abortion. They're confident enough in the efficacy and justice of the U.S. health care system to block funding of the Affordable Care Act. They're confident enough in Wall Street, despite the recklessness and bailouts of the last three years, to press for repeal of the Dodd-Frank financial regulation law. But ask them whether Obama is a Muslim or was born in the United States, and suddenly they're too humble to impose their beliefs on others. They can only describe "the facts as I understand them." They can only speak "for me." They can only "listen to the American people," not "tell them what to think."

These men aren't leaders. They're followers. To lead a party, much less a country, you have to be able to say no. You have to stand up to liars, lunatics, and dupes on your party's fringe. John McCain did it, in his clumsy way (there's nothing wrong with being a Muslim or Arab), when he was the GOP's presidential nominee. Even Bill O'Reilly and Glenn Beck have done it. They've called the birther conspiracy theories "bogus," "absurd," and "ridiculous."

Why can't Boehner, Cantor, or McConnell speak that bluntly? Why won't they call a lie a lie? If they want to be leaders, it's time to lead.